Weird Electrical Issue

First time poster here, and I am glad I found this site. I have a 2004 Elantra with about 68,000 miles on it. The car has never given us any problems until a few weeks ago. While driving down the road, the radio started cutting in and out, then the gauges, then the windows didn't work, etc... Got home parked the car, tried to start the car and discovered the battery was dead. So I figured the alternator was bad. I took the alternator out (thanks to help from this site) and went and had it tested. It tested fine. Charged the battery, put the alternator back in, metered the battery and everything was fine. The car battery was getting charged. Figured the problem was just something loose that I fixed putting the car back together.

One week later, I metered the car while running before heading on a trip and the battery was being drained. So this time I took the battery to get tested and it was fine.

So...anyone have any ideas?